/*
 * Copyright (C) 2015 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.hikyson.godeye.core.internal.modules.leakdetector.canary.android;

import android.app.Activity;
import android.app.Application;
import android.os.Bundle;

import com.squareup.leakcanary.RefWatcher;

import static com.squareup.leakcanary.Preconditions.checkNotNull;

public final class ActivityRefWatcher {

    public static ActivityRefWatcher install(Application application, RefWatcher refWatcher) {
        ActivityRefWatcher activityRefWatcher = new ActivityRefWatcher(application, refWatcher);
        activityRefWatcher.watchActivities();
        return activityRefWatcher;
    }

    private final Application.ActivityLifecycleCallbacks lifecycleCallbacks =
            new Application.ActivityLifecycleCallbacks() {
                @Override
                public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
                }

                @Override
                public void onActivityStarted(Activity activity) {
                }

                @Override
                public void onActivityResumed(Activity activity) {
                }

                @Override
                public void onActivityPaused(Activity activity) {
                }

                @Override
                public void onActivityStopped(Activity activity) {
                }

                @Override
                public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
                }

                @Override
                public void onActivityDestroyed(Activity activity) {
                    ActivityRefWatcher.this.onActivityDestroyed(activity);
                }
            };

    private final Application application;
    private final RefWatcher refWatcher;

    /**
     * Constructs an {@link ActivityRefWatcher} that will make sure the activities are not leaking
     * after they have been destroyed.
     */
    public ActivityRefWatcher(Application application, RefWatcher refWatcher) {
        this.application = checkNotNull(application, "application");
        this.refWatcher = checkNotNull(refWatcher, "refWatcher");
    }

    void onActivityDestroyed(Activity activity) {
        refWatcher.watch(activity);
    }

    public void watchActivities() {
        // Make sure you don't get installed twice.
        stopWatchingActivities();
        application.registerActivityLifecycleCallbacks(lifecycleCallbacks);
    }

    public void stopWatchingActivities() {
        application.unregisterActivityLifecycleCallbacks(lifecycleCallbacks);
    }
}
